Co-production of biofuels and glycols

Abstract

Methods and systems for co-producing higher hydrocarbons and glycols from bio-based feedstocks containing carbohydrates are disclosed.

What is claimed is: 
     
       1. A process of co-producing biofuels and glycols comprising:
 (i) providing a bio-based feedstock stream containing carbohydrates and water; 
 (ii) contacting, in a first reaction system, the bio-based feedstock stream with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 120° C. to 280° C. and 0.1 to 150 bar of hydrogen to produce a hydrogenolysis stream containing at least 5 wt %, based on the total oxygenates content, of glycols that comprises ethylene glycol (EG) and 1,2-propylene glycol (PG), and other monooxygenates; 
 (iii) contacting, in a second reaction system, at least a first portion of said hydrogenolysis stream with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 160° C. to 280° C. and in the presence of 0.1 to 150bar hydrogen to produce an oxygenated intermediate stream comprising at least 5 wt %, based on the total oxygenates, of monooxygenated hydrocarbons of chain length less than 6 carbons; 
 (iv) processing at least a portion of the oxygenated intermediate stream to form a liquid fuel; 
 (v) providing a second portion of said hydrogenolysis stream to a first separation system; 
 (vi) separating a portion of said hydrogenolysis stream, in the first separation system, to a monooxygenates stream comprising monooxygenates and a glycol rich stream comprising at least 10 wt %, based on the total oxygenates, of glycols by flashing; and 
 (vii) recovering glycols from the glycol rich stream. 
 
     
     
       2. The process of  claim 1  wherein further comprising (viii) recycling at least a portion of said monooxygenates stream to the first reaction system. 
     
     
       3. The process of  claim 1  wherein glycols are recovered by separating finished glycol from the glycol rich stream. 
     
     
       4. The process of  claim 1  wherein the glycol content of the hydrogenolysis stream produced in step (ii) is at least 15 wt % based on the total oxygenates content. 
     
     
       5. The method process of  claim 1  wherein the ratio of the hydrogenolysis stream provided to the first separation system and to the second reaction system is in the range of 1.5:1 to 10:1. 
     
     
       6. The process of  claim 1  wherein the maximum steady state temperature of the first reaction system is at least 10° C. less than the maximum steady state temperature of the second reaction system; 
     
     
       7. The process of  claim 6  wherein no process heat from external source is added between the first and second reaction systems, or to the second reaction system, wherein the temperature increase in the second reaction system results from the exothermic heats from the first reaction system and the second reaction system. 
     
     
       8. The process of  claim 4  wherein the glycol rich stream in step (vi) comprises at least 25 wt %, based on the total oxygenates, of glycols. 
     
     
       9. The process of  claim 1  wherein bio-based feedstock is subjected to a digestive solvent to provide bio-based feedstock stream comprising carbohydrates and water. 
     
     
       10. The process of  claim 1  wherein the conversion of carbohydrate in the first reaction system is limited to less than 80%. 
     
     
       11. The method process of  claim 10  wherein the conversion of carbohydrate in the first reaction system is limited to less than 70%. 
     
     
       12. The process of  claim 11  wherein the conversion of carbohydrate in the first reaction system is limited to less than 60%. 
     
     
       13. The method process of  claim 12  wherein the conversion of carbohydrate in the first reaction system is limited to less than 50%. 
     
     
       14. The process of  claim 1  wherein the conversion of carbohydrates to monooxygenated compounds across the first reaction system and the second reaction system is less than 90%. 
     
     
       15. The process of  claim 14  wherein the oxygenated intermediate stream from the second reaction system is flash distilled to provide a stream containing at least a portion of monooxygenate intermediates as feed for production of liquid fuels. 
     
     
       16. The process of  claim 15  wherein the bottoms from flashing containing enriched concentrations of unconverted carbohydrates, sugar alcohols, glycols, and some monooxygenates, are recycle to the first reaction system. 
     
     
       17. A method process of co-producing biofuels and glycols comprising:
 (i) providing a bio-based feedstock; 
 (ii) contacting the bio-based feedstock with a digestive solvent to provide a bio-based feedstock stream containing carbohydrates and water; 
 (iii) contacting, in a first reaction system, the bio-based feedstock stream with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 120° C. to 280° C. and 0.1 to 150 bar of hydrogen to produce a hydrogenolysis stream containing at least 5 wt % , based on the total oxygenates content, of glycols that comprises ethylene glycol (EG) and 1,2-propylene glycol (PG), and other monooxygenates; 
 (iv) contacting, in a second reaction system, at least a first portion of said hydrogenolysis stream with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 160 ° C. to 280 ° C. and in the presence of 0.1 to 150bar hydrogen to produce an oxygenated intermediate stream comprising at least 5 wt %, based on the total oxygenates, of monooxygenated hydrocarbons of chain length less than 6 carbons; 
 (v) processing at least a portion of the oxygenated intermediate stream to form a liquid fuel; 
 (vi) providing a second portion of said hydrogenolysis stream to a first separation system; 
 (vii) separating a portion of said hydrogenolysis stream, in the first separation system, to a monooxygenates stream comprising monooxygenates and a glycol rich stream comprising at least 10 wt %, based on the total oxygenates, of glycols by flashing; and 
 (viii) recovering glycols from the glycol rich stream. 
 
     
     
       18. The process of  claim 17  wherein further comprising (ix) recycling at least a portion of said monooxygenates stream to the first reaction system. 
     
     
       19. The process of  claim 17  wherein glycols are recovered by separating finished glycol from the glycol rich stream. 
     
     
       20. The process of  claim 17  wherein the oxygenated intermediates is subjected to condensation to produce a liquid fuel. 
     
     
       21. The process of  claim 17  wherein the oxygenated intermediates is subjected to dehydration and alkylation to produce a liquid fuel. 
     
     
       22. A process of co-producing biofuels and glycols comprising:
 (i) providing a bio-based feedstock stream containing carbohydrates and water; 
 (ii) contacting, in a first reaction zone, the bio-based feedstock stream with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 120° C. to 280° C. and 0.1 to 150 bar of hydrogen to produce a hydrogenolysis intermediate containing at least 5 wt %, based on the total oxygenates content, of glycols that comprises ethylene glycol (EG) and 1,2-propylene glycol (PG), and other monooxygenates; 
 (iii) contacting, in a second reaction zone, said hydrogenolysis intermediate with hydrogen in the presence of a hydrogenolysis catalyst at a temperature in the range of 160° C. to 280° C. and in the presence of 0.1 to 150 bar hydrogen to produce a combined glycol and oxygenated intermediate stream comprising at least 5 wt %, based on the total oxygenates, of monooxygenated hydrocarbons of chain length less than 6 carbons, and greater than 5 wt % glycols; 
 (iv) separating, by flashing, the combined glycol and oxygenated intermediate stream into a glycol rich stream comprising at least 10 wt %, based on the total oxygenates, of glycols, and a mono-oxygenates-rich stream; 
 (v) processing at least a portion of the monooxygenates-rich stream to form a liquid fuel; and 
 (vi) recovering glycols from the glycol rich stream. 
 
     
     
       23. The process of  claim 22  where the temperature of the second reaction zone is at least 10° C. higher than the temperature of the first reaction zone. 
     
     
       24. The process of  claim 22  where at portion of either or both of the glycol-rich stream or mono-oxygenates rich stream is recycled to provide solvent for the first reaction zone. 
     
     
       25. The process of  claim 24  where the recycled solvent is routed to a digestion zone to digest solid biomass to provide feed for the first reaction zone.